Pitch controlling apparatus of a propeller of ships



6, 1968 TOSHIO ITAZAWA 3,395,762

PITCH CONTROLLING APPARATUS OF A PROPELLER OF SHIPS Filed June 19, 1967 jmv/awfind TasZ-na Itazawa United States Patent 4 Claims. c1. i70-160.32

ABSTRACT OF THE DISCLOSURE In a controllable pitch marine propeller mechanism in which the propeller is connected to the after end of a hollow shaft, a double acting hydraulic cylinder mechanism is nonrotatably fixed forwardly of the front end of the propeller shaft and coaxially therewith. An axially slideable rod extends through the propeller shaft to connect the piston of the hydraulic cylinder with pitch changing mechanism in the propeller hub. The rod comprises two axially aligned members. The forward rod member is connected with the piston and confined to sliding motion therewith. A rotatable connection between the rod members constrains the after rod member to slide fore-and-aft with the forward rod member but leaves it free to rotate with the propeller shaft.

This invention relates to pitch changing apparatus for controllable pitch marine propellers, and pertains more particularly to hydraulic apparatus for actuating the pitch changing mechanism of such a propeller, said apparatus being of the type comprising a double acting cylinder in which a piston is axially slideable and rod means connected with the piston and extending aft therefrom concentrically through a hollow shaft for the propeller.

Heretofore the conventional apparatus for actuating the pitch changing mechanism of a controllable pitch marine propeller has been as illustrated in FIGURE 1, which is a view partly in side elevation and partly in longitudinal section of the gear case, propeller shaft and pitch change actuating mechanism for such a propeller. The propeller shaft, designated generally by E, was hollow and comprised three coaxially aligned sections, namely, an after section 0 to the rear of which was connected the propeller (not shown), a forward section Q which comprised a gear axle and which had an enlarged gear hub R formed intermediate its ends, and a coupling W which connected the after end of the forward section Q with the forward end of the after section 0 and constrained the shaft sections to rotate in unison. By means of reduction gearing A that comprised gear teeth P on the rim of the gear hub R the propeller shaft was drivingly connectable with an engine (not shown). A gear case D enclosed the reduction gearing A and all but the after end portion of the forward propeller shaft section Q.

The forward shaft section Q had a large diameter bore in its gear hub portion R that served as a cylinder in which a piston S was slideable fore-and-aft to provide a doubleacting hydraulic actuator. The piston S was in turn connected with a rod C that extended coaxially through the hollow propeller shaft and had its after end disposed in the propeller hub for actuation of pitch changing mechanism. The rod C comprised two axially aligned rod members connected by a connector X that was located in the coupling W of the shaft. The mechanism by which foreand-aft motion of the rod C was converted into variation of the pitch of the propeller blades is well known and is not affected by the present invention, and is therefore not shown.

I 3,395,762 Patented Aug. 6, 1968 ice Inasmuch as the cylinder and piston comprising the hydraulic actuator, together with the rod C, all rotated with the propeller shaft, pressure fluid had to be conducted to and from the cylinder through a rotary sliding seal. To this end the hub portion R of the forward shaft section Was provided with oil passages T that respectively extended a short distance forward and aft from the cylinder, in parallelism with the shaft axis but eccentric thereto, and each of which terminated in a radially outwardly opening mouth portion that communicated with an inwardly opening circumferential groove U in an oil ring L. Each oil ring L was rigidly fixed in the gear case D and had a close sliding fit around the forward section of the propeller shaft. Communicating bores V in the gear case and in each oil ring provided ports through which oil could be directed int-o and out of the oil rings and thence to and from the hydraulic actuator.

In the arrangement just described, it was obviously of the utmost importance that there be a very good sealing fit between the rotating forward section Q of the propeller shaft and each of the fixed oil rings L. In practice, however, the required rotary seal was virtually unattainable, with the result that there was always a certain amount of oil leakage at this point, which leakage frequently became excessive.

Inasmuch as precise control of propeller pitch was dependent upon accurate fore-and-aft positioning of the piston S, and this was in turn dependent upon accurate metering of oil flow to and from the hydraulic cylinder at each side of the piston, any leakage at the oil rings L caused instability of propeller pitch control. Because of the sliding joint between the propeller shaft and the oil rings L, the oil rings would wear rapidly and had to be replaced frequently to prevent instability of propeller pitch control from exceeding tolerable limits.

Further, because of the inaccessible location of the hydraulic actuator, within the hub of the driven gear and intermediate the forward and after ends of the forward shaft section Q, repair and replacement of the packing rings for the piston S and of the packing for the rod C was difficult and time consuming.

By contrast, it is a general object of the present invention to provide a pitch change actuator mechanism for a controllable pitch marine propeller wherein there is a nonrotating hydraulic actuator accessibly mounted forwardly of the propeller shaft on a gear case so as to eliminate sliding oil seals and the problems attendant upon them.

Another object of this invention is to provide a pitch change actuator mechanism for a marine propeller which is arranged to permit quick and easy access to the rings of the hydraulic actuator piston and the packings for the rod member that connects said piston with the pitch altering mechanism in the propeller.

It is also a general and very important object of this invention to provide a pitch change actuator mechanism for a controllable pitch marine propeller that provides very stable and accurate propeller pitch control with substantially less maintenance and repair than has heretofore been necessary with such mechanisms.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claims.

The accompanying drawing illustrates one complete example of the physical embodiment of the invention, constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIGURE 2 is a view generally similar to FIGURE 1 but illustrating a propeller pitch change actuator mechanism embodying the present invention.

Referring now more particularly to FIGURE 2, the pitch change actuator mechanism of this invention comprises, in general, a gear case D having an upper section I and a lower section K, the upper section I being generally concentric to an input shaft 1 that is connectable with an engine (not shown) and the lower section K being generally concentric to a hollow fore-and-aft extending propeller shaft E which has a propeller (not shown) connected to its after end. A double acting bydraulic actuator H is non-rotatably mounted at the front of the lower section of the gear case, and the piston 16 of said actuator is connected with a rod C that extends through the hollow propeller shaft and has its after end connected with conventional pitch changing mechanism (not shown) in the hub of the propeller.

The input shaft 1 is drivingly connectable with the propeller shaft through a clutch (not shown) that is located in the after portion B of the upper case section I and through reduction gearing A comprising a driving gear 3 that is concentric with the driving shaft 1 and a larger driven gear 4 on the propeller shaft.

The propeller shaft E, as is more or less conventional, comprises a forward section 2 that provides an axle for the driven gear 4, a coaxial after section 13 which can be considered the propeller shaft proper, and a medial coupling G which connects the forward and after shaft sections and constrains them to rotate in unison.

The gear axle or forward section 2 of the propeller shaft is journaled in a pair of radial thrust bearings 26 that are located at opposite sides of the driven gear 4 and are carried by the gear case, and it is axially confined by a pair of end thrust bearings 27, similarly located at opposite sides of the gear 4, inwardly of the bearings 26, and carried by the gear case.

The coupling G of the propeller shaft has a substantially large bore therethrough and has a radially outwardly projecting flange 34 on each of its ends. On the rear end of the forward shaft section 2 and on the front end of the after shaft section 13 there are flanged collars 22, each of said collars having its flange opposing one of the flanges 34 on the coupling G and connected thereto by means of bolts 25 that extend through the adjacent flanges parallel to the shaft axis. Each of the flanged collars 22 has a tapering bore and telescopes over a correspondingly tapered portion of its shaft section, while a nut 23, threaded onto the extreme end portion of the shaft section, cooperates with the taper in the shaft section to prevent axial displacement of the collar relative to the shaft. A key 24 constrains each collar to rotate with its shaft section, and the coupling G thus causes the after propeller shaft section 13 (the propeller shaft proper) to rotate with the gear axle 2.

The cylinder of the hydraulic actuator H is shown as comprising a generally tubular cylinder body 15 and end wall members 20 and 21, the after end wall member 20 being fixed to the gear case to further serve as a forward wall of the lower gear case section K. Pressure oil passages 17 open radially from the bore in the cylinder body 15 to provide for flow of oil to and from the interior of the cylinder, and it will be observed that these passages can be connected directly with suitable pipes or tubes (not shown) inasmuch as the cylinder is fixed with respect to the gear case.

The rod C comprises a forward member 31 which is coupled to an after member 32 means of a rotatable connector which is described hereinafter and which is located within the propeller shaft coupling G. The front end portion of the forward rod member 31 has a reduced diameter and is received in a closely fitting coaxial bore in the piston 16. A nut 19, threaded onto the extreme front end portion of the forward rod member and received in a forwardly opening counterbore in the piston, constrains the rod to fore-and-aft motion with the piston.

Projecting coaxially forwardly from the front end of the rod is a guide member 18 which is preferably of smaller diameter than the rod and can be formed integrally with the forward rod member. The guide member 18 extends through a closely fitting bore in the forward wall 21 of the cylinder and into a bracket 29 that is fixed on said wall and projects forwardly therefrom. A transverse pin 30 on the front end of the guide member 18 is slideably received in closely fitting longitudinal slots in the bracket 29 to cooperate with the bracket in guiding the rod in fore-and-aft motion and in preventing rotation of the rod and the piston.

The rotatable connector which couples the rod members 31 and 32 comprises a collar nut 10 threaded onto the front end of the after rod member 32, a bushing 8 and thrust bearings 5 held in place on the rear end portion of the forward rod member 31 by means of a nut 9 that is threaded onto the rear extremity of said rod member 31, and a longitudinally split sleeve 11 having radially inwardly projecting circumferential flanges and which embraces the collar nut 10 and the bearings 5.

The bushing 8 fits on a reduced diameter portion of the forward rod member 31 near its rear extremity and is confined against both rotational and axial motion relative to said rod member by the nut 9. The bearings 5, which surround the bushing 8 and are held in axially spaced relation by it, serve to journal the split sleeve 11 so that it can rotate about the forward rod member 31 with the coupling G of the shaft. An annular spacer 12 is confined axially between the collar nut 10 and the outer race of the rear thrust bearing 5.

It will be apparent that the coupling G of the propeller shaft confines the parts of the split sleeve 11 against lateral separation. It will also be apparent that the split sleeve is slideable fore-and-aft in the bore of the coupling G but that the split sleeve and the after rod member 32 tend to rotate with the propeller shaft while the forward rod member 31 is confined to fore-and-aft motion, the bore in the forward propeller shaft section 2 being large enough to provide clearance all around the forward rod member 31.

The hydraulic actuator H can be readily disassembled because of its accessible location of the front of the lower section of the gear case. Such disassembly also provides for ready access to glands in the end wall members 20 and 21 of the cylinder that provide seals around the forward rod member 31 and the guide member 18, respectively.

From the foregoing description taken with the accompanying drawing it will be readily apparent that this invention provides a pitch changing actuator for a controllable pitch marine propeller whereby accurate propeller pitch control can be consistently maintained without the need for frequent repair or replacement of parts, and comprising a readily accessible double-acting hydraulic cylinder that can be quickly and easily disassembled for replacement of piston rings and rod packing.

What is claimed as my invention is:

1. In combination with a controllable pitch marine propeller, a rotatable shaft having an after section at the rear of which the propeller is secured, a forward section and a hollow coupling that connects the rear end of the forward section with the front end of the after section and constrains said sections to rotate in unison, and means comprising a concentric gear on said forward section of the rotatable shaft for drivingly connecting the same with an engine, means for actuating the pitch changing mechanism of the propeller comprising:

(A) a double acting hydraulic actuating cylinder in which a piston is constrained to fore-and-aft sliding motion;

(B) means fixing said cylinder forwardly of the forward section of the rotatable shaft and concentric therewith;

(C) a first rod member extending coaxially through the forward section of the shaft and projecting beyond the opposite ends thereof, said first rod member having a connection with the piston at its front end by which it is constrained to fo-re-and-aft sliding motion with the piston;

(D) a second rod member extending coaxially through the after section of the shaft and projecting beyond the opposite ends of the same, said second rod member being slideable fore-and-aft relative to said after section of the shaft; and

(E) means in said hollow coupling section providing a rotatable connection between the adjacent end portions of the first and second rod members by which they are constrained to fore-and-aft motion in unison but whereby the second rod member can partake of rotation of the rotatable shaft while the first rod member is confined to fore-and-aft motion.

2. The combination of claim 1 further characterized by the last named means comprising:

(A) an enlarged collar fixed on the forward end portion of the second rod member;

(B) a bearing encircling the rear end portion of the first rod member, said bearing being confined against axial motion relative to the first rod member; and

(C) a longitudinally split sleeve encircling said collar and said bearing, said sleeve being axially slideable in the hollow coupling and being held against lateral separation thereby, and said sleeve having axially inwardly facing shoulders at its opposite ends which respectively engage axially opposite end faces on the collar and on the bearing to confine the rod members against axial separation, said sleeve being journaled on the hearing so that it can rotate with the shaft and with the second rod member.

3. A controllable pitch marine propeller mechanism of the type comp-rising a gear case in which there is a driving gear connectable with an engine and a driven gear, a rotatable shaft having a forward section to which the driven gear is concentrically connected, a coaxial after section to the rear of which the propeller is connected, and a hollow coupling that connects said shaft sections for rotation in unison, "a double acting hydraulic cylinder in which a piston is slideable fore-and-aft, and rod means extending coaxially through the rotatable shaft for transmitting fore-and-a-ft motion of the piston to pitch changing mechanism in the propeller, said mechanism being characterized by:

(A) said hydraulic cylinder being fixed to the gear case forwardly of the front end of the rotatable shaft and coaxially therewith; and (B) said rod means comprising (1) a (forward rod member which extends coaxially th-rough the forward section of the rotatable shaft and projects beyond the opposite ends thereof, said forward rod member being connected to the piston at its front end so as to be constrained to fore-and-after motion with the piston,

(2) an after rod member which extends coaxially through the after section of the rotatable shaft and is slideable fore-and-aft relative thereto and can rotate therewith, and

(3) means in said hollow coupling providing a rotatable connection between the rear end of the forward rod member and the front end of the after rod member by which said rod members are constrained to fore-and-aft motion in unison while the after rod member is permitted to rotate with the shaft and relative. to the forward r member.

4. The combination of claim 1, further characterized by: 1

(A) a guide member coaxially secured to the piston and projecting coaxially forwardly therefrom out of the hydraulic cylinder through a closely fitting bore in its front wall;

(B) a transverse pin fixed on the front of said guide member; and

(C) bracket means on the front of the cylinder having fore-and-aft extending guide surfaces between which said transverse pin is received and which cooperate with it in preventing rotation of the piston and first rod member, the position of the pin along said guide surfaces also providing visible indication of propeller pitch.

References Cited UNITED STATES PATENTS 2,946,317 7/1960 Klaassen et al. -16037 X 3,092,186 6/ 196-3 MacLean 170160.45 3,148,735 9/1964 Miller et al. 170160.32 3,269,121 8/1966 Bening 170l60.32 X

FOREIGN PATENTS 566,757 4/ 1958 Belgium. 1,104,473 6/ 1955 France.

496,087 11/1938 Great Britain.

644,534 10/1950 Great Britain.

EVERETTE A. POWELL, IR., Primary Examiner. 

